The 34-year-old has agreed to a deal that will keep him at Parc des Princes for the 2017-18 season - with Goal having revealed in June that a 12-month extension was in place.
However, the former Barcelona man says he is thrilled to continue his "adventure" with PSG.
"It's a great pleasure to extend my contract with Paris Saint-Germain," he said. "I have a special history with this club, who have put a lot of confidence in me over the last five years.
"The adventure continues and I'm very happy. We will continue to be competitive and we'll give the maximum to go as far as possible in all the competitions we take part in."
President Nasser Al-Khelaifi added: "We're very pleased to have extended Thiago's contract.
"Thiago Motta is an important member of the squad and his leadership and knowledge of the game are really appreciated by our supporters.
"He is certainly one of those to have contributed greatly to the growth of Paris Saint-Germain, both in France and internationally."
Motta has won four Ligue 1 titles, four Coupes de la Ligue, four Trophees des Champions and three Coupes de France since joining from Inter in 2012.